1. Field of the Invention
The present invention relates to a self-dispersion pigment excellent in dispersion stability in an aqueous medium, a production process thereof, an ink set and an ink jet recording method.
2. Description of the Related Art
In recent years, attention has been paid to pigments excellent in light resistance and water resistance compared with dyes as coloring materials for aqueous inks used in ink jet recording. However, since a pigment is insoluble in water, the pigment needs to be stably present in water for using it as a coloring material of an aqueous ink. Treatment techniques for pigments for stably dispersing a pigment in an aqueous medium have recently come to be actively developed. Among these techniques developed, such a technique of making a pigment self-dispersible that pigment itself is treated to improve the dispersibility of the pigment itself, thereby making it a self-dispersion pigment dispersible in an aqueous medium without using any dispersant is particularly favorably used as techniques for treating pigments for ink jet aqueous inks, because reliability with respect to an ink jet head is high.
As one of the above-described techniques for treating the pigment itself, Japanese Patent Application Laid-Open No. H08-3498 describes a technique for oxidatively treating a pigment with an oxidizing agent. Japanese Patent No. 4001922 describes a technique for treating a pigment with a diazonium salt.